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| Titel |
Impacts of AMSU-A, MHS and IASI data assimilation on temperature and humidity forecasts with GSI–WRF over the western United States |
| VerfasserIn |
Y. Bao, J. Xu, A. M. Jr. Powell, M. Shao, J. Min, Y. Pan |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 8, no. 10 ; Nr. 8, no. 10 (2015-10-14), S.4231-4242 |
| Datensatznummer |
250116635
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| Publikation (Nr.) |
 copernicus.org/amt-8-4231-2015.pdf |
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| Zusammenfassung |
| Using NOAA's Gridpoint Statistical Interpolation (GSI) data
assimilation system and NCAR's Advanced Research WRF (Weather Research and Forecasting) (ARW-WRF) regional
model, six experiments are designed by (1) a control experiment (CTRL) and
five data assimilation (DA) experiments with different data sets, including
(2) conventional data only (CON); (3) microwave data (AMSU-A + MHS) only
(MW); (4) infrared data (IASI) only (IR); (5) a combination of microwave and
infrared data (MWIR); and (6) a combination of conventional, microwave and
infrared observation data (ALL). One-month experiments in July 2012 and the
impacts of the DA on temperature and moisture forecasts at the surface and
four vertical layers over the western United States have been investigated.
The four layers include lower troposphere (LT) from 800 to 1000 hPa, middle
troposphere (MT) from 400 to 800 hPa, upper troposphere (UT) from 200 to
400 hPa, and lower stratosphere (LS) from 50 to 200 hPa. The results show that
the regional GSI–WRF system is underestimating the observed temperature in
the LT and overestimating in the UT and LS. The MW DA reduced the forecast
bias from the MT to the LS within 30 h forecasts, and the CON DA kept a
smaller forecast bias in the LT for 2-day forecasts. The largest root mean square
error (RMSE) is observed in the LT and at the surface (SFC). Compared to the CTRL, the MW
DA produced the most positive contribution in the UT and LS, and the CON DA
mainly improved the temperature forecasts at the SFC. However, the IR DA
gave a negative contribution in the LT.
Most of the observed humidity in the different vertical layers is
overestimated in the humidity forecasts except in the UT. The smallest bias
in the humidity forecast occurred at the SFC and in the UT. The DA experiments
apparently reduced the bias from the LT to UT, especially for the IR DA
experiment, but the RMSEs are not reduced in the humidity forecasts.
Compared to the CTRL, the IR DA experiment has a larger RMSE in the
moisture forecast, although the smallest bias is found in the LT and MT. |
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